
Many aspects of tank building can get a tad immersive, and spawn a few late nights. Weathering is one that grabs many builders/enhancers. I use these, Stu (above):
They come with something that looks like a make-up brush (and no, I don't wear makeup, just a touch of polyfilla for the cracks

). Well, it's a combi brush and dabber/smearer to be accurate. You can get some sensational effects with them.
I know... 'cos I've seen folk do it.
For my part, I'm still learning how to get the best out of them.

"Get your facts first, and then you can distort them as much as you please"- Mark Twain.